Electoral clustering in Brazil’s state of Rio de Janeiro is a way of grouping municipalities (or even voting zones/sections) that behave similarly at the ballot box—based on patterns like vote shares, turnout, invalid/blank rates, and how those metrics shift across elections. When you run clustering on precinct-level results, Rio typically breaks into a few “behavioral geographies” that don’t always match administrative boundaries: the metropolitan core (Rio city), the Baixada Fluminense, coastal corridors (e.g., Região dos Lagos / Costa Verde), and interior regions such as the Serrana and Norte/Noroeste Fluminense often form distinct blocs because they differ in demographics, urbanization, income, public-service access, and issue priorities. The practical value is campaign-grade: clusters help you see where persuasion is plausible versus where mobilization is the better play, so you can tailor messaging, field operations, and media spend to the “political microclimates” inside one state that’s anything but uniform.

https://human-squared.com/wp-content/uploads/2026/02/mapa_rj_clusters_filtro_municipio_v5.html